You do have a right to privacy if your getting calls regarding an in-law you've never even spoken with. These people buy old spreadsheets at pennies on the dollar that list debt that people may or may not have already paid off. They have no legal right to collect money they did not lend, but they will take it if people agree to pay them. This is a shady business already, but leaving daily messages to get relatives to harass someone who may have owed money to a third part is a violation of privacy.